JQGrid Column name from Table-Collection of common programming errors

Am working on JQGrid and i got this doubt on how to implement.

Currently am displaying standard set of results to user every time as given in examples.

colNames:['Inv No no NO','Date', 'Client', 'Total in EUR']

Suppose if am changing this result set i will change in .js file (add or remove column) of JqGrid.

Is there a any way i can bring these Column names from Table and Bind it to JqGrid ?

Also how do i ADDcolumn names at runtime ? like adding new Column and all.

Thanks